Abstract To address the need for a more diverse biomedical and biobehavioral research workforce, and to increase opportunities for effective mentoring for diverse and underrepresented groups, we propose to implement a group peer mentoring program for academic physician-scientists and PhD scientists engaged in biomedical research that will result in enhanced career advancement and success, and high vitality. We will conduct a randomized controlled trial of group peer mentoring with mid-career faculty participants, as they are at a critical career transition point. Our primary outcomes are measures of faculty vitality and career advancement. Hypothesized secondary outcomes include enhanced cultural awareness and appreciation of difference and diversity; use of key mentoring practices, and achievement of personal goals. Short- term, intermediate and long-term outcomes will be measured by the following methods: validated survey instruments; self-assessment (surveys and written narratives with qualitative analysis); CV analysis for DPC Hallmarks of Success; supervisor assessment. Specific factors that contribute to the successful intervention will be assessed including the mechanisms of relationship formation, providing psychological safety, reciprocity, cultural awareness and appreciation of difference and diversity; and a structured process of academic career planning. We will conduct qualitative analyses of ethnographic observation, participant interviews and written narratives to assess the mechanisms, and participants will report on completion of each step of the detailed academic development plan. This scientific approach to understanding a successful mentoring intervention will contribute to the science of mentoring; be a basis for broad dissemination of the intervention methods and mechanisms; and will be generalizable to different institutions and career stages. The proposed evidence-based mentoring model eliminates the frequently encountered pitfalls of traditional mentoring models and their variable success, and provides a network of peers. One arm of the project is to assess the use of mentoring practices learned in the intervention by gathering the perspectives of the intervention participants' own home work groups. In this way, the specific factors that contribute to successful outcomes will be disseminated across a wide variety of institutions in the US.